Screwdriver



R. BARANY July 17, 1962 SCREWDRIVER Filed May 12. 1960 ill I .25)

WI'IIIIIII ntor ERT R FIG. 7 by: j

United States This invention relates to screwdrivers and more particularly to a non-slip screwdriver adapted to drive a screw having a slotted head with a centrally disposed hole in the screw head of greater diameter than the width of the slot.

Such screws when driven by a screwdriver having a blade portion adapted to coincide with the slot and a central pin adapted to fit more or less snugly into the hole possess the advantage of precluding longitudinal movement of the blade in the slot and thus ensure precise centering and registration of the screwdriver blade and the screw head at all times; Moreover theuse of the circular slot possesses certain manufacturing advantages not available in the use of screws having slots with central holes of a cross section other than circular.

By way of example screws and screwdrivers therefor of this class are shown in such prior United States patents as No. 1,797,390, No. 2,431,628 and No. 2,522,164.

This invention relates to an improved form of screw ,and screwdriver adapted to drive such screws and to the combination of such a screwdriver and screw.

It is an object of the invention to provide such a screwdriver as will be easily and thus relatively inexpensively assembled and manufactured.

It is a further important object of this invention to provide such a screwdriver as will afford non-slip actuation of screws of the class described.

It is a further important object of this invention to provide such a screwdriver as will permit the screw to be driven with one hand only, it being unnecessary to hold or retain the screw in operative position with the other hand while driving the same.

These and other advantageous objects will become apparent through the consideration of the following detailed description taken in conjunction with the attached drawings in which:

FIGURE 1 is a perspective view of a screw of the class adapted to be driven by the screwdriver forming the subject matter ofthis invention.

FIGURE 1a is a perspective view of an alternative screw adapted to be driven by the screwdriver forming the subject matter of this invention.

FIGURE 2 is a perspective view of a screwdriver constructed and assembled according to one embodiment of this invention.

FIGURE 3 is an exploded perspective view of the screwdriver shown in its assembled form in FIGURE 2.

FIGURE 4 is a cross section of the screwdriver shown in FIGURE 2 in assembled form.

FIGURE 5 is an exploded perspective view similar to FIGURE 3 but showing an alternative embodiment of the invention.

FIGURE 6 is a perspective view of the embodiment of the invention shown in FIGURE 5, in semi-assembled condition.

FIGURE 7 is a perspective view of a further alternative embodiment of the invention.

The invention consists broadly of a screwdriver adapted to actuate a screw having a stem with a head, at least one slot bisecting the head and a central hole in the head of greater diameter than the width of the slot which comprises a shank, a pin of the proper diameter to fit snugly into the hole in the screw head, extending therefrom, a

arent G I attests; Patented July 17, 1962 diametric slot in the pin and in at least theoutermost portion of the shank and a blade member adapted to fit into the screw slot and adapted to fit snugly in the shank slot and relatively more freely in the slot in the projecting portion of the pin, the blade having an outermost extremity substantially coinciding with the outermost projection of the pin and extending laterally beyond the circumference of the pin but not substantially beyond the circumference of the shank.

Referring now to the drawings, 1 illustrates the type of screw in connection with which it is proposed to use the screwdriver forming the subject matter of this invention.

Such screws have a stem 2 with a head 3 and a slot 4 bisecting the head. The head also has a central hole 5 of substantially greater diameter than the width of the slot 4 but not necessarily of any significantly greater depth than the width of the slot.

As shown in FIGURE 11: the screw constructed according to a preferred embodiment of the invention contains two slots biseoting the head at right angles to each other. In FIGURE 1a the slot 4a is perpendicular to the slot 4. The use of the doubly slotted head afiords an important advantage when the screwdriver is power driven in that it aiIords twice the opportunity of registering the screwdriver blade in the slot within a given arc. With the advent of power driven tools, this case of registration is an important feature and for this reason the slot in FIGURE la is a preferred embodiment of this invention.

A screwdriver constructed so as to embody features of 7 this invention and adapted to drive the screws in FIGURE 1 or FIGURE 1a is shown in its assembled form in FIG- URE 2 and in its exploded form in FIGURE 3. This screwdriver comprises four members namely a shank 6, a pin 7, a blade 8', and retaining means 9, all as hereinafter described in detail. The shank 6 in this embodiment has a centrally disposed bore 10 extending from one end thereof. The bored end of the shank 6 is diametrically slotted as at 11 this slot extending from the outermost extremity to a point short of the end of the bore 10. This bored and slotted outermost extremity of the shank 6 is adapted to receive in snug press fitted relationship, the pin 7; the length of the pin being such that when it is pressed fully home into the bored end of the shank 6 the pin projects beyond the outermost extremity of the shank 6 by a distance substantially equal to but not significantly greater than the depth of the hole 5 in the head of the screw 1. The bore 10 and the pin 7 press fitted thereinto are of substantially the same diameter as the diameter of the hole 5 in the head of the slot of the screw 1 so that the outermost extremity 12 of the pin 7 may fit snugly into the hole 5 in the manner hereinafter described in detail. The outermost extremity of the pin 7 is slotted as at 13 the slots being slightly wider than the slots 11 in the shank 6 and being of suflicient depth to coincide with the slots 11 of the shank 6 when the pin is driven home into its press fitted relationship in the shank 6.

After the pin is so inserted it is rotated so that the slots 13 register with the slots 11.

The slots 13 and 11 are such that the blade member hereinafter described fits tightly into slots 11 so as to be retained therein, but relatively more freely in slots 13 so that the slotted outer extremity of the pin may expand to fit snugly and with a certain limited degree of tolerance, into the central hole in the head of the screw.. The slotted nature of the pin not only permits the easy assembly of the entire unit but also permits the pin to fit snugly and securely into screw holes of slightly varying diameters thus retaining the screw on the driver blade and permitting one handed actuation of the screw.

The screwdriver also includes a blade member 8. This blade member is formed of a sheet of substantially flat 3 rigid material and of such a thickness as to fit snugly into the slots 4 in the head of the screw 1 the slots 11 in the shank are also of such thickness as to receive this plate tightly, the slots 13 in the pin being slightly wider for reasons already pointed out.

The length of the plate is such that when inserted into the registered slots 11' and 13 its outermost extremity substantially coincides with the outermost extremity of the pin 7 and its width is such that while it projects laterally beyond the circumference of the pin, it does not extend substantially beyond the circumference of the shank 6.

The screwdriver is assembled by press fitting the pin 7 into the bore 10 of the shank 6 driving it fully home, registering the slots 11 and 13 and inserting the plate 8 into the slots so as to assume the relationship shown in FIGURES 2 and 4.

Some means is required to hold the shank, pin and slot in this thus assembled condition. In the embodiment shown in FIGURES 2 to 4 inclusive, the retaining means comprises a retaining ring 9 a circumferen-tialgroove 14 in the slot and two oppositely disposed nicks 15 in the blade, the retaining ring being adapted to fit into the groove 14 and the nicks 15 and hold the parts in assem bled relationship as may be seen by reference to FIG- URES 2 and 4.

An alternative means whereby the parts may be retained in their assembled relationship is shown in FIG- URES 5 and 6. According to. this embodiment the shank 6 with its bored port-ion 14) diameter bisecting slots 11 as well as the pin 7 with its slots 13 remain unchanged from the embodiment shown in FIGURES 2 to 4. In this embodiment however the blade member 8 is shaped to have an outermost or projecting portion 16 of a Width between the diameter of the slot 7 and the outside diameter of the shank 6 and an innermost width substantially equalto the diameter of shank 6. When this blade is placed into the registered slots in the manner shown in FIGURE 6, a cap 18 having an outermost flange 19 shaped with an aperture adapted to fit over the pin 7 and the lateral extension there beyond of the outermost portion 16 of the blade 8 is adapted to fit tightly over the outermost portion of the shank 6 and thus by means of the flange 19, retain the assembly in the proper relationship.

FIGURE 7 illustrates a further possible alternative to this invention. In this case the pin is integral with the shank being in fact the same piece turned further down. The slot thus bisects not only the outermost portion of the pin, but also at least the extremity of the shank, the

blade fitting tightly into the shank slot.

According to one important embodiment of this invention at least the outermost portion of the-pin 7 is formed of tempered steel imparting to it qualities of resilience which will become importantvfor reasons which will become apparent hereafter.

The screwdriver constructed and assembled according to the teaching of this invention offers several notable advantages. Firstly it comprises a minimum of parts and these pants all being of simple design and configuration may be read-1y made and assembled with the most basic machine tools.

Secondly the fact that the outermost extremity 12 of the pin 7 is slotted at 13 allows for a certain degree of expansion in the outermost projecting extremity of the pin 7 so that this pin may be fitted very closely into the hole 5 in the head of the screw 1 the degree of expansion aiforded by the slotted projection of the pin thus retaining the screw on the screwdriver without the necessity of holding the screw with the other hand. This degree of expansion and its consequent advantages are enhanced through tempering the pin in the manner already described.

The invention has been described with reference to preferred embodiments. It is to be understood how- 4 ever that the invention is not limited to the precise embodiments shown nor to precise constructional details thereof. Such embodiments of the invention as come with-in the scope and purview of the appended claims are to be considered as part of this invention.

What I claim as my invention is:

l. A screwdriver adapted to drive a screw having a stem with a head, at least one slot bisecting the head and a central hole in the head of greater diameter than the width of the slot, said screwdriver comprising a shank, a pin of lesser diameter than the shank secured to the shank and having a portion including an end projecting beyond the shank, the projecting portion of the pin being adapted to fit snugly into the hole in the head of the screw, a diametric slot in said pin, the diametric slot having an open end at said end of said pin, a second diametric slot in at least the outermost portion of the shank, a blade member comprising a substantially flat plate of rigid material, said blade member being of sufiicient thickness to fit into the slot in the head of the screw, and fitting tightly in the shank slot and relatively more freely in the portion of the pin slot projecting beyond the shank, said plate having an outermost extremity substantially coinciding with the outermost projection of the pin, and extending laterally beyond the circumference of the pin, and means for retaining the shank and blade member together in assembled and operative relationship.

2. A screwdriver adapted to drive a screw having a stem with a head, a slot bisecting the head and a central hole in the head of greater diameter than the width of the slot, said screwdriver comprising a shank having a centrally disposed bore in one end thereof, the walls of the bored end of the shank being diametrically slotted, a pin seated in said bore and having a portion including an end protruding beyond the shank, the protruding portion of the pin being adapted to fit snugly into the hole in the head of the screw, a diametric slot in said pin co inciding with the slots in the shank when said pin is pressed therein, the diametric slot in said pin having an open end at said end of said pin, a blade member comprising a substantially flat plate of rigid material, said blade member being of suiiicient thickness to fit into the slot in the head of the screw, and fitting tightly in the shank slots, said plate having an outermost extremity substantially coinciding with the outermost projection of the pin, and extending laterally beyond the circumference of the pin, and means for retaining the shank, pin and blade member together in assembled and operative relationship.

3. A screwdriver as claimed in claim 2 in which at least the protruding portion of the pin is of steel tempered so as to impart resilient properties thereto.

4. A screwdriver as claimed in claim 3 wherein said retaining means comprises a circumferential groove on the shank, nicks on the blade edge coinciding with said groove when the screwdriver is in assembled condition and a retaining ring fitting into the groove and nicks to retain the screwdriver in assembled relationship.

5. A screwdriver as claimed in claim 3 wherein said retaining means comprises a collar having a flange with an aperture receiving the protruding of the pin and said one end of said blade, said collar being press fitted on to the shank to'retain the screwdriver in assembled relationship.

6. A screwdriver as claimed in claim 3 wherein said 7 blade is substantially the same width as the outside diameter of the shank.

7. A screwdriver adapted to drive a screw having a stem with a head, at least one slot bisecting the head and a central hole in the head of greater diameter than the width of the slot, said screwdriver comprising a shank, a blade member projecting from one end of the shank and being of sufficient thickness to fit into the slot in the head 5 of the screw, and a central pin of greater diameter than the width of said blade member and less diameter than said shank secured to said shank and having a portion including an end projecting from said one end of said References Cited in the file of this patent UNITED STATES PATENTS Hulsrnann Oct. 31, 1911 Levedahl May 19, 1925 Blackburn May 10, 1938 Fieg July 2, 1940 Olsen Dec. 30, 1941 FOREIGN PATENTS Australia Feb. 5, 1948 

